Apparatus for filtration



Oct. 17, 1933. F. x. Gow-:Rs 1,931,000

APPARATUS FOR FILTRAT ION Filed Dec. 27, 1932 2 Sheets-Sheet 1 @AMW Oct.17, 1933. 1 F, X @VERS 1,931,000

APPARATUS FOR FILTRATION Filed Deo. 27, 1932 2 Sheets-Sheet 2 PatentedOct. 17, 1933 A i i APPARATUS Foa FILTRATION Francis X. Govers,Vincennes, Ind., assignor to Indian Relining Company, Lawrenceville,lll., a Icorporation of Maine i Application December 27, 1932 Serial No.648,869

4 Claims. (ci. 2ML-192) This invention relates to a method of andapnated. This is tedious, and in the case oi ilocparatus for filteringor separating solids from culent precipitates which settle withdiiilculty a liquids and particularly wherein a mass of sepagreat amountof time is consumed and, in addirated and suspended solids may be washedor tion, the removal of the salts of reaction may.

5 extracted with asolvent to remove soluble connever be complete.

stituents. In the forming of precipitates or crystals of My inventioncontemplates an improved lchemical compounds, it is very diicult to formter apparatus comprising a. illter of the leaf precipitates Wherein allPortions of the precipi` type provided with internal stirring means fortate are f even Size; and it is Still more dimcult 0 maintaining thealtering mixture of liquid and to obtain crystals of uniform size. Dueto this "5 solids suspended therein in /a suitable condilack ofuniformity, it is Very diiilcult to obtain tion of turbulence within theillter to produce a deposit Which is comparatively uniform in rapidmtratiofl': and uniform deposition of the deposition, either upon thewalls of a centrifuge solids on the riltering surface. It also provides01' upon the Surface of a filtering medium and 5 a means i'or supplyingsolvent wash to the face due to this uneven deposition it is almost imofthe filter cake while maintaining a suitable Possible, due tochanneling, to completely and condition of turbulence productive oi'rapid washevenly Wash the deposited Solids Without the ing and uniformdistribution of solvent throughuse of undue amounts of solventextractive maout the filter cake mass. terial- This application is acontinuation-impart of The use of undue amountsof Solvent extrac- 75 myycopending application, serial No. 585,844, tives in the case ofcompounds that ere even med January 11y 1932, for method of andapslightly soluble in the solvent results in undeparatus for mtl-ationsired contamination of the illtrate where the n1- An important featureof my invention is this trate contains the desired Duriiled Products, or

provision of stirring arms within the filter means loss of materialWhere the separated Solids are adaptable for effecting the rapid andeasy disthe desired Product. charge of the iilter cake in the form of aslurry Unevenness of siZe in Precipitation or crystalfrom the' filteringmeans without the necessity lization frequently gives masses that can beillof Opening the filter, tered only with great dimculty due to thefact' 3 The apparatus of lmy invention is adapted to that by segregationthey form'dense deposits on 85 the filtration of mixtures containingsolid or the lfiltering surface that are Practically imperseinirsolidmaterial or precipitates of jelly-nire vious to the passage of liquids.Attempts to preconsistency which lack what are generally revent thisdense deposit 0f separated Small partiferred to as free-filteringqualities and which, cies have been made by designing nlters of the asdeposited, are difficult to filter out of the revolving leaftiipey suchas the Oliver and Val- 90 mother liquor. This condition is particularlylez, Where the iotation -of the leaf is Supposed to noticeable incertain salts or compounds of aluresult in even deposition of thefiltering material. mina, and in certain precipitations produced byPresses of this type, however, are not of the Wash chilling a solutionoi petroleumhydrocarbon in type and cannot be used for this Purpose. The

0 a selective solvent. The invention is particuordinary Wash nlter oftheplate and frame type 95 larly well adapted to the removal of paratllndoes not permit of an even distribution of the wax from chilledsolutions of wax-bearing oil Washing media. and Parts of the mass areoverlin suitable solvent liquids. washed and parts are decidedlyunderwashed.

lIn the puniication of many chemicals, as 'for In the case of many typesof precipitates which example, aluminum hydroxide, blanc iixe or aredifilcult to Wash, it has been found advanta- 100 barium sulphate, etc.,the purification frequent- Seous to stir the mixture underflltrationsuf- 1y has to be of a; very high degree and difficultyciently to prevent any substantial deposition on is found in washingfrom the precipitated solids the filter blankets, and when the materialunder the mother liquor and salts of reaction, mtration is Sumcientlythickened, then introducordinarily the salts of reaction distributed ingthe wash solvent while maintaining the pre- 105 throughout aprecipitated mass of material are cipitate in suspension. When theWashing is removed by washing with a solvent while stircompleted, theprecipitate is removed from the ring. settling the washed precipitateand dcillterin a slurry which is filtered in a Plate and canting theliquid layer. This process is repeated frame type filter to the desiredPercentage oi' 5 until the salts of reaction are practicallyelimlsolids, or is dried directly to the desired state o! 110 idrynessin a drier, advantageously, of the spray ype.

In order to describe the invention, reference will now be made to thefigures of the accompanying drawings forming a part of thisspecification in which: I

Fig. 1 is a view of the filter and its connections with a portion of theshell cut away to illustrate the interior thereof, and

Fig. 2 is a View of the interior of the filter taken along the line 2-2of Fig. l.

In Figs. l and 2, the filter comprises a cylindrical body portion 1 andtwo circular end plates, 2a and 2b, forming the ends of the cylindricalbody portion and clamped in position with bolts 3 extending throughcorresponding holes at regular intervals around the peripheral edges ofthe plates. Corresponding grooves 4 are provided in the ends of the body1 and the portion of the inner faces -of the plates 2a and 2b contiguousthereto, in which packing or gasket material may be inserted. Instead ofemploying gasket material, these contiguous edges may be ball-jointed inorder to make a leakproof joint.

The inner and adjacent faces of the -plates 2a and 2b are cut away toform circular recesses l5 havingsubstantially .the same diameter as theinternal diameter of the body portion l.

A grid 6 extends across the recesses of both plates spaced a short'distance therefromr by a spacer 7 and secured to the plates by screws8. Filter cloth, or other fabric material suitable as a filteringsurface,is laid over the grid and advantageously secured in position byhaving its outer edge clamped between the ends of the body portion 1 andthe plates 2 and 2b and with its inner edges secured to the centralportion of the plates by clamps 9.

The center of each plate 2a and 2b is drilled to provide bearings 10 and11. The bearing 10 extends all the way through the center of the plate2*, while bearing 11 advantageously extends 4only partiway through theplate 2b. A stufiing box 12 is rigidly secured to the outer side of theplate 2*, adjacent to the bearing 10 forming a part of the bearing andprovided with a packing gland 13. A shaft 14 extends through thestufiing box 12 and is rotatably supported within the bearings 10 and11. Suitable driving means, such as a motor, may be provided forrotating the shaft at any desired speed.

Mounted on the shaft 14, and rigidly secured thereto, between the plates2B and 2b, is a hub 15. A plurality of stirring arms 16 and 16bextending radially outwards from the hub are secured thereto at regularintervals about the hub.

These stirring arms may be of any suitable shape. Although not shown inthe drawings, an advantageous form of construction may comprise stirringarmsof flat section adjustably mounted upon the hub 15 and also adaptedto be set so that their faces will form different angles with respect tothe axis of the hub l5. In this way, the position of the stirring armsmay be altered to permit varying the clearance between the edges of thestirring arms and the adjacent fiiteringsurfaces.

Stationary baiiles 16c are secured at4 intervals about the inner surfaceof the shell 1 and project inwardly towards the hub 15 midway betweenthe filtering surfaces so as not to interfere with the rotation of therevolving arms 16Aa and 16". The centrally disposed fixed bafflesprevent the formation of a substantial mass of solid material betweenthe adjacent filtering surfaces,

and which would rotate, or tend to rotate, with the revolving arms, andalso cause the filter cake to revolve relatively to the filteringsurface. These fixed bafiies act as breakers and permit maintainingsufficient turbulence within the filtering solution to prevent gravitysettling without, at the same time, hindering the deposition of solidsupon the vertical filter surfaces in the form of a filter cake whichdoes not move rela.- tively to the filter surface in the manner justmentioned.

The arms 16a and 16", as shown in the drawings, revolve in the spacebetween the stationary baffles and the filtering surfaces and in closeproximityV to the latter. When arranged in this fashion the spacebetween the revolving arms 16u and 16b should, of course, be adjusted soas to permit formation of a filter cake of customary thickness.

Although the drawing illustrates a filter shell having a single pair offilter spaces with the spaces and filtering-elements forming the filtershell, it is contemplated that the filter could comprise a plurality ofsuch filtering elements and spaces provided with a plurality of ofstirring arms, or the filter may comprise an independent drum or shellcontaining one or more hollow filter leavessupported therein and havingrevolving stirring arms mounted between such pair of leaves. Whilestationary filter surfaces have been described, it is contemplated thatmy invention may be advantageously applied toa filter having rotatingleaves.

In the'operation of the filter as, for example' in connection with aprocess for the separation of wax from hydrocarbon oils, a chilledmixture consisting of wax-bearing mineral oil and a solvent liquid,which latter may comprise, for example, 65% of benzol and 35% ofacetone, is,

introduced to the space between the filtering surfaces through a pipe 17leading from a chill- 'ing tank or other source of supply not shown.

The filtrate passes through the filtering surface into the recessedportions 5 from which it,

is withdrawn through a pipe 18. Wax or solid hydrocarbons -contained 'orsuspended in theV mixture introduced to the lter is deposited on thesurface of the filter cloth. During ltration,

the shaft 14 with the stirring arms 16 and 16b attached thereto isrotated, usually at a slow rate of speed, say about 10 R. P. M., inorder to keep the solid hydrocarbons in suspension in the liquidhydrocarbons until deposited upon the filtering surface.

When a cake of desired thickness has been formed, a quantity of freshchilled solvent mixture may be introducedto the interior of the filterthrough a pipe 19 to wash out any mother liquor adhering to the cake. During this washing step, the operation of the stirring mechanism iscontinued.

Upon completion of the washing of the cake, the filtrate discharge pipe18 is closed and chilled solvent liquid is introduced until the filterisentirely filled. The speed of the rotating arms is then increased to arelatively high rate, say

until about 80 R. P. M. is reached. Due to the' violently turbulentcondition thus produced within the filter, the cake is dislodged fromthe filtering surface and converted into a slurry which is thendischarged from the filter through a pipe 20.

If desired, a displacing medium, such as gas under pressure or any othersuitable fluid means, may be introduced to the -lter through a pipe 2lto facilitate discharging the filter cake slurry from the lter.

Obviously many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claims.

i' claim:

l. A filter apparatus comprising a. closed shell, hollow filteringelements supported within the shell at spaced intervals, a shaftextending axially through the shell and filter elements and rotatablysupported therein, stirring arms secured to said shaft extendingradially outward therefrom and adapted to revolve between the adjacentfilter elements, stationary baies secured to the inner surface of thefilter shell extending inwardly towards said shaft between adjacentfilter elements and adapted to effect, in cooperation with the revolvingarms, turbulence of the filtering mixture and to prevent movement of thefilter cake relative to the filtering surface, means for rotating theshaft, means for introducing the mixture to be filtered to the interiorof the shell surrounding the filter elements, and means for removingltrate from the interior of the elements.

2. A filter apparatus comprising a closed shell, hollow filteringelements supported within the shell at spaced intervals, a shaftextending axially through the shell and filter elements and rotatablysupported therein, stirring arms secured to said shaft adapted torevolve between the elements and within close proximity to the filteringsurface of each filter element, stationary baflies secured to the innersurface of the filter shell extending inwardly towards said shaftsubstantially midway between the filter elements, and adapted to effect,in cooperation with the revolving arms,`

-ing surface, means for rotating the shaft, means to the interior of theshell surrounding the filter elements, and means for removing filtratefrom the interior of the elements.

3. A filter apparatus comprising a horizontal cylindrical shell, aplurality of hollow filtering elements supported within the shell andspaced at short intervals throughout its length, a shaft extendingaxially through the shell and through openings provided in the center ofeach filter element and rotatably supported in the ends of said shell,stirring arms secured to said shaft extending radially outward therefromand adapted to revolve between the adjacent filter elements, stationarybaffles secured to the inner surface of the filter shell extendinginwardly towards said shaft between adjacent filter elements and adaptedto effect, in cooperation with the revolving arms, turbulence of thefiltering mixture and to prevent movement of the filter cake relative tothe filterfor introducing the mixture to be filtered to the interior ofthe shell surrounding the filter elements, and means for removingfiltrate from the interior of the elements.

4. A filter apparatus comprising a shell, a pair of adjacent filteringsurfaces within the shell, a shaft extending axially through the shelland filter surfaces and rotatably supported therein, stirring armssecured to said shaft extending radially outward therefrom and adaptedto revolve between the adjacent filter surfaces, stationary bafflessecured to the inner surface of the filter shell extending inwardlytowards said shaft between adjacent filter surfaces and adapted toeffect, in cooperation with the revolving arms, turbulence of thefiltering mixture and to prevent movement of the filter cake relative tothe filtering surface, means for rotating the shaft, means forintroducing the mixture to be filtered to the filter shell, and. meansfor removing 115 filtrate after passage through the filtering surfaces.

FRANCIS X. GOVERS.

